Acute coronary syndrome (ACS) is an umbrella term referring to a set of signs and symptoms, for example chest pain, that are results of a sudden decrease in blood flow to the heart (i.e., cardiac ischemia). ACS includes unstable angina, and two forms of heart attacks, non-ST elevation myocardial infarction (NSTEMI), and ST-elevation myocardial infarction (STEMI). About 1.5 million patients per year are diagnosed with ACS in the United States.